A phone-based hearing test has been launched to try to persuade an estimated 4m people that they could benefit from a hearing aid.

The Royal National Institute for Deaf people (RNID) says 4m people are losing their hearing but doing nothing about it and hopes to change their attitudes.

A survey by pollsters Mori suggested embarrassment was the main reason people did not discuss hearing loss.

The RNID hopes people will feel more comfortable calling 0845 600 5555.

By the time we reach 60, over half of us will have some level of hearing loss

John Low

The Mori survey - commissioned by the RNID - also found that nearly three-quarters of people with impaired hearing, who had not consulted a GP or a hearing specialist, said they did not think their hearing was "bad enough" to seek help.

More than a quarter of those questioned thought hearing aids made people look "old", and one in five felt that using a hearing aid would mean that they would be treated differently.

MORI spoke to more than 2000 adults for the survey which was conducted last month.

The RNID has responded to the findings by launching a campaign called Breaking the Sound Barrier with the help of the Countess of Wessex.

People are being encouraged to use an automated telephone hearing test which is introduced by broadcaster, Eamonn Holmes.

Advertising campaign

The test has been validated by an audiology expert - Professor Mark Lutman - from Southampton University.

The caller is asked to listen to a succession of sound clips and enter the numbers they hear spoken into their key pad.

A series of TV advertisements to raise awareness will also start on Christmas Day.

"By the time we reach 60, over half of us will have some level of hearing loss," said RNID chief executive, John Low.

"It can have a profound impact on our personal and professional lives, leaving many of us feeling isolated and out of touch with family, friends and colleagues."

Breaking the Sound Barrier is part of the RNID's long-term aim to improve the take-up of hearing aids.

The organisation says that people who take action to address their hearing loss not only benefit themselves, but also their family, friends and colleagues.

The campaign launch also featured the first public performance of a piece of music called Fanfare for the Hard of Hearing, commissioned from composer, Laurence Mark Wythe.

Mr Wythe said it was the most challenging commission he had ever accepted.

"People who are losing their hearing say the extremities of pitch are the first sounds they lose," he said.

"I used that connection as my starting base with the boundless possibilities of sound that need to be cherished and sought after, lest we take them for granted."

The RNID also has the backing of a number of celebrities including Sir Cliff Richard, Claire Rayner, Alan Titchmarsh and historian David Starkey.

Earlier this year the charity asked a number of designers to rethink the way hearing aids look and the resulting work went on display at London's Victoria & Albert Museum.